Self-retaining anti-rotation clip

ABSTRACT

A self-retaining anti-rotation clip for a spherical-bearing rod end has two opposing spacer plates, each spacer plate having a curved edge portion for surrounding at least a portion of a ball of the rod end. A connector plate connects the spacer plates, such that the spacer plates are spaced from each other and generally parallel to each other. Retaining means are carried on the clip and adapted for retaining each spacer plate in a position generally adjacent one side of a body of the rod end, such that the spacer plates are free from interference with the ball of the rod end.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/523,601, filed 17 Jul. 2009 titled “Self-Retaining Anti-RotationalClip,” which claims the benefit of International PCT Application No.PCT/US07/03597, filed 2 Sep. 2007, titled “Self-RetainingAnti-Rotational Clip,” both of which are hereby incorporated byreference for all purposes as if fully set forth herein.

BACKGROUND

1. Field of the Present Description

The technical field is self-retaining anti-rotation clips.

2. Description of Related Art

Spherical bearings are often used to connect objects that move inrelation to each other, such as links in a linkage, and the sphericalbearings allow for limited relative movement about multiple axes.However, it may be desirable to use spherical bearings without allowingcomplete freedom of movement about all axes. To limit rotation ofspherical bearings used in rod ends, anti-rotation clips have beendisclosed in the prior art, such as the clips disclosed in U.S. Pat. No.4,072,431 to Waight et al. and U.S. Pat. No. 6,371,681 to Covington etal. These anti-rotation clips are distinguishable from protective orcushioning boots for rod ends, such as those disclosed in U.S. Pat. No.2,064,692 to Shank and U.S. Pat. No. 5,203,522 to White et al.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an oblique view of a spring-damper assembly having installedthereon self-retaining anti-rotation clips according to a firstembodiment.

FIGS. 2A through 2D show oblique, side, and sectional views of anassembly of a spherical-bearing rod end and a clip of FIG. 1.

FIG. 3 is an end view of an assembly comprising the rod end and clip ofFIGS. 2A through 2D.

FIG. 4 is a side view of a portion of an aircraft, the spring-damperassembly of FIG. 1 being shown installed on the aircraft.

FIGS. 5A through 5D show oblique, side, and sectional views of anassembly of a spherical-bearing rod end and another embodiment of aself-retaining anti-rotation clip.

FIGS. 6A through 6D show oblique, side, and sectional views of anassembly of a spherical-bearing rod end and another embodiment of aself-retaining anti-rotation clip.

FIGS. 7A through 7D show oblique, side, and sectional views of anassembly of a spherical-bearing rod end and another embodiment of aself-retaining anti-rotation clip.

FIGS. 8A through 8D show oblique, side, and sectional views of anassembly of a spherical-bearing rod end and another embodiment of aself-retaining anti-rotation clip.

FIGS. 9A through 9D show oblique, side, and sectional views of anassembly of a spherical-bearing rod end and another embodiment of aself-retaining anti-rotation clip.

DETAILED DESCRIPTION

A self-retaining anti-rotation clip for a spherical bearing limitsrotation of the race of the bearing relative to the ball of the bearingwhen it is installed on the bearing and when the assembly is installedin a clevis or other type of mount. The clip may also be used with aspherical bearing installed in a rod end, wherein the clip limitsrotation of the body of the rod end when it is installed on the rod endto form an end assembly and when the end assembly is installed in aclevis or other type of mount.

The clip comprises means for retaining the clip on the spherical bearingor rod end prior to installation of the assembly. The clip is preferablyformed from a relatively soft, wearable plastic or a similar elastomericmaterial, and use of these materials requires a design that differs fromprevious designs of anti-rotation clips. For example, the sacrificialspacer plates and connector plate of each clip need to have increasedsurface area to prolong life of the clip and reduce or eliminate wear ofthe attached components. The embodiments shown in the figures anddescribed below show the use of self-retaining anti-rotation clips withrod ends, but it should be understood that the clips may be used withspherical bearings in other types of appropriate assemblies.

FIG. 1 shows a spring-damper assembly 11, which comprises aspring-damper 13 and end assemblies 15 located at each end ofspring-damper 13. Each end assembly 15 comprises a spherical-bearing rodend 17 and a self-retaining anti-rotation clip 19 assembled onto rod end17. In the embodiment of FIG. 1, clip 19 is assembled onto rod end 17prior to attachment of rod end 17 to spring-damper 13.

FIGS. 2A through 2B show oblique, side, and sectional views of one endassembly 15. Rod end 17 is a spherical-bearing rod end, comprising anouter bearing housing, or race, carried within a rigid body 21, aspherical ball 23 rotatably carried within the outer housing and body21, and a connector 24 extending from body 21 and configured forattachment to an object. Body 21 is shaped to allow ball 23 to protrudefrom opposing sides of body 21. Ball 23 is shown with a diametric bore25 extending through body 23, and bore 25 is configured for receiving afastener (an example is shown in FIG. 3) for attaching rod end 17 to anobject. Ball 23 is capable of rotation within body 21 about axes 27, 29,31, allowing for relative rotation between body 21 and ball 23. Atapered portion 32 is formed on each side of body 21 that extends toconnector 24 and may include a defined shoulder. Clip 19 is configuredto be assembled onto rod end 17 for substantially limiting relativerotation between body 21 and ball 23 to rotation primarily about axis31.

Clip 19 is preferably formed from relatively soft, wearable plastic or asimilar elastomeric material and comprises two spacer plates 33, aconnector plate 35, and retaining means 37 for retaining clip 19 on rodend 17. Spacer plates 33 are attached to connector plate 35 in aconfiguration that positions spacer plates 33 apart from each other andorients spacer plates 33 as generally parallel to each other. Connectorplate 35 is shown with a curved profile, but connector plate 35 mayalternatively be formed to have a profile of another shape. In theembodiment of FIGS. 2A through 2D, spacer plates extend from connectorplate 35 for a length that is approximately equal to the length of body21 of rod end 17. Holes 37 are formed in spacer plates 33 to allow afastener to pass through clip 19 and ball 23. In addition, an inner edgeor surface of each hole 37 encircles the adjacent protruding portion ofball 23 and acts as retaining means for retaining clip 19 on rod end 17.Though shown as having a straight wall, hole 37 may have a tapered orcurved wall, such as a chamfer or bevel. Spacer plates 33 have athickness t, as shown in FIG. 2C, that is preferably less than thedistance ball 23 protrudes from each side of body 21. Connector plate 35also has a hole 39 for receiving connector 24 of rod end 17, and thisconfiguration minimizes rotation of clip 19 relative to body 21.

To install clip 19 on rod end 17, clip 19 is oriented to align connector24 with hole 39 of connector plate 35. Connector 24 is inserted intohole 39, and rod end 17 and clip 19 are oriented to allow body 21 toslide between spacer plates 33. As the protruding portions of ball 23engage the outer ends of spacer plates 33, plates 33 elastically deformaway from each other, allowing ball 23 to pass between plates 33. Spacerplates 33 spring back toward each other as ball 23 enters holes 37,retaining clip 19 on rod end 17 and positioning spacer plates 33generally adjacent body 21, as shown in FIG. 2C.

FIG. 3 is an end view of an example installation of an end assembly 15in a clevis mount formed by clevis portions 41A, 41B. A fastener is usedto retain end assembly 15 within clevis portions 41A, 41B. In theexample shown, a bolt 43 comprises a head 45 and a shaft 47, which isinserted through clevis portion 41A, through one spacer plate 33,through ball 23, through the other spacer plate 33, and through clevisportion 41B. Shaft may, for example, have external threads (not shown)for engaging threads of a nut 49 on the opposite side of the assemblyfrom head 45. As can be seen in the figure, spacer plates 33substantially fill the space between an inner face of each clevisportion 41A, 41B and the corresponding side of body 21, limitingrotation of body 21 about axes perpendicular to axis 31 while allowingsubstantial rotation about axis 31. As mentioned above, thickness t ofspacer plates 33 is preferably less than the distance ball 23 protrudesbeyond the sides of body 21, and this allows clevis portions 41A, 41B tobe tightened against ball 23 while providing clearance for rotation ofspacer plates 33 primarily about axis 31 relative to clevis portions41A, 41B.

FIG. 4 is a side view of a portion of an aircraft with an installedspring-damper assembly 11. A transmission 51 for a helicopter is mountedwith a transmission support 53 to an airframe 55. Transmission support53 allows for limited movement of transmission 51 relative to airframe55, and spring-damper assembly 11 is mounted between transmission 51 andairframe 55 for damping this motion. An end assembly 15, comprising arod end 17 and a clip 19, is attached to each end of spring-damper 13,and each end assembly 15 is attached to one of a pair of clevises 57,59. Clevis 57 is attached to transmission 51, and spring-damper assembly11 is attached to clevis 57 with a fastener 61 in a similar manner asshown in FIG. 3. Likewise, clevis 59 is attached to transmission support53 and airframe 55, and spring-damper assembly 11 is attached to clevis59 with fastener 63. Clips 19 maintain body 21 of each rod end 17 in agenerally vertical orientation, preventing each body 21 from contactingclevis 57, 59, which may cause binding or undesirable wear of clevises57, 59 or bodies 21. In this manner clips 19 serve as replaceable,sacrificial elements.

FIGS. 5A through 5D, 6A through 6D, 7A through 7D, 8A through 8D, and 9Athrough 9D are views of alternate embodiments of self-retaininganti-rotation clips.

FIGS. 5A through 5D show oblique, side, and sectional views of an endassembly 65, comprising a rod end 17, as described above, and aself-retaining anti-rotation clip 67. Clip 67 is configured to beassembled onto rod end 17 for substantially limiting relative rotationbetween body 21 and ball 23 to rotation primarily about axis 31. Clip 67is generally C-shaped and preferably formed from relatively soft,wearable plastic or a similar elastomeric material. Clip 67 comprisestwo spacer plates 69, a connector plate 71, and retaining means 73 forretaining clip 67 on rod end 17. Spacer plates 69 are attached toconnector plate 71 in a configuration that positions spacer plates 69apart from each other and orients spacer plates 69 as generally parallelto each other. In the embodiment of FIGS. 5A through 5D, spacer platesextend from connector plate 71 for only a portion of the length of body21 of rod end 17. An inner edge 75 is formed on spacer plates 69, theinner edge 75 partially surrounding the adjacent protruding portion ofball 23. Spacer plates 33 have a thickness t, as shown in FIG. 5C, thatis preferably less than the distance ball 23 protrudes from each side ofbody 21. A lip 73 is formed on each end of connector plate 71, and eachlip 73 engages tapered portion 32 to retain clip 67 on rod end 17. Asshown, lips 73 engage a shoulder of tapered portion 32, though ashoulder is not required. The shape of connector plate 71 cooperateswith lips 73 to minimize rotation of clip 67 relative to body 21.

To install clip 67 on rod end 17, clip 67 is oriented to allow body 21to slide between spacer plates 69. As lips 73 engage body 21, lips 73elastically deform away from each other, allowing body 21 to passbetween lips 73. Lips 73 spring back toward each other as the widestportion of body 21 passes lips 73, as shown in FIG. 5D, retaining clip67 on rod end 17 and positioning spacer plates 69 generally adjacentbody 21, as shown in FIG. 5C.

FIGS. 6A through 6D show oblique, side, and sectional views of an endassembly 77, comprising a rod end 17, as described above, and aself-retaining anti-rotation clip 79. Clip 79 is configured to beassembled onto rod end 17 for substantially limiting relative rotationbetween body 21 and ball 23 to rotation primarily about axis 31. Clip 79is generally C-shaped and preferably formed from relatively soft,wearable plastic or a similar elastomeric material. Clip 79 comprisestwo spacer plates 81, a connector plate 83, and retaining means 85 forretaining clip 79 on rod end 17. Spacer plates 81 are attached toconnector plate 83 in a configuration that positions spacer plates 81apart from each other and orients spacer plates 81 as generally parallelto each other. In the embodiment of FIGS. 6A through 6D, spacer platesextend from connector plate 83 for only a portion of the length of body21 of rod end 17. An inner edge 87 is formed on spacer plates 81, theinner edge 87 partially surrounding the adjacent protruding portion ofball 23. Spacer plates 81 have a thickness t, as shown in FIG. 6C, thatis preferably less than the distance ball 23 protrudes from each side ofbody 21. To retain clip 79 on rod end 17, a lip 85 is formed on an innersurface of each spacer plate 81 that engages a curved inner surface 91,such as a staking groove, of body 21. As shown, each lip 85 is formed asa curve to generally mimic the curvature of inner surface 91. The shapeof connector plate 83 cooperates with lips 85 to minimize rotation ofclip 79 relative to body 21.

To install clip 79 on rod end 17, clip 79 is oriented to allow body 21to slide between spacer plates 81. As lips 85 engage body 21, spacerplates 81 elastically deform away from each other, allowing body 21 topass between lips 85. Spacer plates 81 spring back toward each other aslips 85 pass inner surface 91, as shown in FIG. 6C, retaining clip 79 onrod end 17 and positioning spacer plates 81 generally adjacent body 21,also shown in FIG. 6C.

FIGS. 7A through 7D show oblique, side, and sectional views of an endassembly 93, comprising a rod end 17, as described above, and aself-retaining anti-rotation clip 95. Clip 95 is configured to beassembled onto rod end 17 for substantially limiting relative rotationbetween body 21 and ball 23 to rotation primarily about axis 31. Clip 95comprises two preferably identical pieces and is preferably formed fromrelatively soft, wearable plastic or a similar elastomeric material. Inthe embodiment shown, the two pieces of clip 95 are formed by bisectingclip 95 with a plane normal to axis 31. Each piece of clip 95 comprisesa spacer plate 97, half of connector plate 99, and retaining means 101for retaining clip 95 on rod end 17. Each spacer plate 97 is attached tothe associated half of connector plate 99 in a configuration thatpositions spacer plates 97 apart from each other and orients spacerplates 97 as generally parallel to each other. In the embodiment ofFIGS. 7A through 7D, the pieces of clip 95 assemble to form an enclosurearound rod end 17, and each piece has a hole 103 encircling theassociated protruding portion of ball 23. Spacer plates 97 have athickness t, as shown in FIG. 7C, that is preferably less than thedistance ball 23 protrudes from each side of body 21. To retain clip 95on rod end 17, cooperating tab fasteners 101 are formed on each piece ofclip 95, each portion of tab fasteners 101 on one piece of clip 95engaging a corresponding portion on the other piece of clip 95 to retainthe pieces together. Connector plate 99 has a hole 105 for receivingconnector 24 of rod end 17, one half of hole 105 being formed in eachpiece of clip 95. This configuration minimizes rotation of clip 95relative to body 21. To install clip 95 on rod end 17, each piece ofclip 95 is oriented to align with the appropriate features of rod end 17and the pieces are snapped together using tab fasteners 101. Thispositions spacer plates 97 generally adjacent body 21, also shown inFIG. 7C.

FIGS. 8A through 8D show oblique, side, and sectional views of an endassembly 107, comprising a rod end 17, as described above, and aself-retaining anti-rotation clip 109. Clip 109 is configured to beassembled onto rod end 17 for substantially limiting relative rotationbetween body 21 and ball 23 to rotation primarily about axis 31. Clip109 comprises two preferably identical pieces and is preferably formedfrom relatively soft, wearable plastic or a similar elastomericmaterial. In the embodiment shown, the two pieces of clip 109 are formedby bisecting clip 109 with a plane that contains axis 31 and bisectsbody 21 of rod end 17. Each piece of clip 109 comprises half of eachspacer plate 111, half of connector plate 113, and half of retainingmeans 115 for retaining clip 109 on rod end 17. Each half of spacerplate 111 is attached to the associated half of connector plate 113 in aconfiguration that positions spacer plates 111 apart from each other andorients spacer plates 111 as generally parallel to each other. In theembodiment of FIGS. 8A through 8D, the pieces of clip 109 assemble toform an enclosure around rod end 17, and each piece has half of each oftwo holes 117 encircling the associated protruding portion of ball 23.Spacer plates 111 have a thickness t, as shown in FIG. 8C, that ispreferably less than the distance ball 23 protrudes from each side ofbody 21. To retain pieces of clip 109 to each other and retain clip 109on rod end 17, cooperating tab fasteners 115 are formed on each piece ofclip 109, each portion of tab fasteners 115 on one piece of clip 109engaging a corresponding portion on the other piece of clip 109 toretain the pieces together. Connector plate 113 has a hole 119 forreceiving connector 24 of rod end 17, one half of hole 119 being formedin each piece of clip 109. This configuration minimizes rotation of clip109 relative to body 21. To install clip 109 on rod end 17, each pieceof clip 109 is oriented to align with the appropriate features of rodend 17 and the pieces are snapped together using tab fasteners 115. Thispositions spacer plates 111 generally adjacent body 21, also shown inFIG. 8C.

FIGS. 9A through 9D show oblique, side, and sectional views of an endassembly 121, comprising a rod end 17, as described above, and aself-retaining anti-rotation clip 123. Clip 123 is configured to beassembled onto rod end 17 for substantially limiting relative rotationbetween body 21 and ball 23 to rotation primarily about axis 31. Clip123 comprises two preferably identical sides and is preferably formedfrom relatively soft, wearable plastic or a similar elastomericmaterial. In the embodiment shown, the two sides of clip 123 are formedby bisecting clip 123 with a plane that contains axis 31 and bisectsbody 21 of rod end 17. Each side of clip 123 comprises half of eachspacer plate 125, half of connector plate 127, and half of retainingmeans 129 for retaining clip 123 on rod end 17. Each half of spacerplate 125 is attached to the associated half of connector plate 127 in aconfiguration that positions spacer plates 125 apart from each other andorients spacer plates 125 as generally parallel to each other. In theembodiment of FIGS. 9A through 9D, the sides of clip 123 are connectedto each other with an integral hinge 131, and the sides close in a“clamshell” manner to form an enclosure around rod end 17. Each side hashalf of each of two holes 133 encircling the associated protrudingportion of ball 23. Spacer plates 125 have a thickness t, as shown inFIG. 9C, that is preferably less than the distance ball 23 protrudesfrom each side of body 21. To retain sides of clip 123 to each other andretain clip 123 on rod end 17, cooperating tab fasteners 129 are formedon each side of clip 123, each portion of tab fasteners 129 on one sideof clip 123 engaging a corresponding portion on the other side of clip123 to retain the sides together. Connector plate 127 has a hole 135 forreceiving connector 24 of rod end 17, one half of hole 135 being formedin each side of clip 123. This configuration minimizes rotation of clip123 relative to body 21. To install clip 123 on rod end 17, clip 123 isoriented to align the sides with the appropriate features of rod end 17and the sides are hinged toward each other and snapped together usingtab fasteners 129. This positions spacer plates 125 generally adjacentbody 21, also shown in FIG. 9C. Though shown with hinge 131 being formedon an end of clip 123, hinge 131 may be formed in another location ororientation on clip 123.

It should be noted that each of the features shown in the embodimentsdescribed above may be used in combination with features shown inanother embodiment. For example, a lip, configured like lip 85 of FIGS.6A through 6D, may be used on any of the embodiments to assist inlocating the clip on the rod end. It should also be noted that clips 95,109, and 123 are shown and described as preferably being bisected intoidentical sides or pieces, though it is not required that the sides orpieces be identical. Clips 95, 109, 123 may be formed to havenon-identical sides or pieces, wherein unequal portions of connectorplates, spacer plates, or other features, such as holes, may be formedon the sides or pieces.

The self-retaining anti-rotation clip provides for several advantages,including: (1) the clip remains assembled on a spherical bearing or rodend when the bearing or rod end is detached from another object; (2) theclip has low weight and cost through the use of plastic or elastomericmaterial; (3) the clip is easy to install and uninstall; (4). the cliprequires no modification to the spherical bearing, rod end, or clevisportions; and (5) the clip is sacrificial. When sufficient clearancearound rod end 17 exists, clips 67, 79, 109, and 123 have the additionaladvantage of being installable or replaceable without the need todisassemble rod end 17 from the associated clevis.

While this invention has been described with reference to illustrativeembodiments, this description is not intended to be construed in alimiting sense. Various modifications and combinations of theillustrative embodiments, as well as other embodiments of the invention,will be apparent to persons skilled in the art upon reference to thedescription.

What is claimed is:
 1. A self-retaining anti-rotation clip for aspherical-bearing rod end, the rod end comprising a body and a sphericalball rotatably carried within the body, the rod end also having aconnector for attaching the rod end to another object, the clipcomprising: first and second completely separable opposing spacerplates, each spacer plate having a curved edge portion adapted forsurrounding at least a portion of a ball of a rod end; a connector plateconnecting the spacer plates comprising a first half extending from thefirst spacer plate and a second half extending from the second spacerplate, such that the spacer plates are spaced from each other andgenerally parallel to each other and that the first spacer plate and thefirst half of the connector plate are identical in shape and size to thesecond spacer plate and the second half of the connector plate; afastener attached to an outer surface of the clip and configured tosecure each spacer plate to each other in a position generally adjacentone side of a body of the rod end, such that the spacer plates are freefrom interference with the ball of the rod end, the fastener having: afirst tab positioned on and protruding from an outer surface of thefirst half of the connector plate; and a second tab positioned on andprotruding from an outer surface of the second half of the connectorplate; wherein the first tab is configured to snap into the second tab,which in turn retains the spacer plates in a fixed position relative toeach other; and a hole formed by the connector plate for receiving theconnector of the rod; wherein the two spacer plates are substantiallyplanar and are secured together solely by the fastener; wherein anycross section of each the clip in a plane parallel to the spacer platesdefines a strictly convex space or shape such that the two spacer platesand the connector plate are configured to solely surround the entirebody of the rod end.
 2. The self-retaining anti-rotation clip accordingto claim 1, wherein the clip is adapted to substantially enclose thebody of the rod end.
 3. A self-retaining anti-rotation clip for aspherical bearing, the spherical bearing comprising an outer housing anda spherical ball rotatably carried within the housing, the clipcomprising: first and second completely separable opposing spacerplates, each spacer plate having a curved edge portion adapted forsurrounding at least a portion of a ball of a spherical bearing; aconnector plate connecting the spacer plates comprising a first halfextending from the first spacer plate and a second half extending fromthe second spacer plate, such that the spacer plates are spaced fromeach other and generally parallel to each other and that the firstspacer plate and the first half of the connector plate are identical inshape and size to the second spacer plate and the second half of theconnector plate; and a fastener attached to an outer surface of the clipand configured to secure each spacer plate in a position generallyadjacent one side of an outer housing of the spherical bearing, suchthat the spacer plates are free from interference with the ball of thespherical bearing, the fastener having: a first tab positioned on andprotruding from an outer surface of the first half of the connectorplate; and a second tab positioned on and protruding from an outersurface of the second half of the connector plate; wherein the first tabis configured to snap into the second tab, which in turn retains theopposing plates in a fixed position relative to each other; wherein thetwo spacer plates are substantially planar and are secured togethersolely by the fastener; wherein any cross section of each the clip in aplane parallel to the spacer plates defines a strictly convex space orshape such that the two spacer plates and the connector plate areconfigured to solely surround the entire body of the outer housing. 4.The self-retaining anti-rotation clip according to claim 3, wherein thecurved edge of each spacer plate defines a hole.
 5. The self-retaininganti-rotation clip according to claim 3, wherein the curved edge of eachspacer plate defines a hole; and wherein the hole in each spacer plateis adapted to encircle the ball of the spherical bearing.
 6. Theself-retaining anti-rotation clip according to claim 3, wherein the clipis adapted to substantially enclose the spherical bearing.